Clear-Com 4000 series II, Technical Manual

Page: 104 / 134

Technical Manual Issue 2.1 4000 Digital Series
II
Page 80 STA0381
A green LED is provided on the front of the unit to indicate that the unit power supply is operating
correctly.
4.4.5 PDE 4642 Microprocessor Card (MPC)
Figure 75 - PDE4642 Microprocessor Card
The PDE4642 is the main processor card for 4000 series II systems.
It runs on a 68360 processor at 25 MHz and contains a 64kbyte/128kbyte boot PROM, one 8Mbyte
SIMM DRAM, 256kbyte of battery backed SRAM and 2 Mbytes of flash ROM.
The 68360 contains four serial ports , two are used for RS232/RS422 channels (U63 is the transceiver
), one is for ethernet (U68) which will auto-sense AUI or 10BaseT interface, and the other is used for
inter-processor communication in the case of redundancy.
The card also drives the main audio clocks for a system: U41 provides a 16MHz balanced ECL signal,
a sample rate clock and a x64 sample rate clock are also provided by U42.
U48 is a phase comparator for locking the VCXO(U39) to an external source.